Design of circularly polarized patch antenna array with H-shaped apertures

A novel circularly polarization microstrip antenna array operated in S band is presented. The antenna array consists of four subarrays. The dual feeds are placed in orthogonal directions, and are connected to the Wilkinson power divider with the microstrip 90 degree phase shift between its two output feedlines. The patch is coupled by two orthogonal H-shaped apertures, which can enhance the isolation of the two ports and improve the circularly polarized performance. The antenna array gain is 14 dBic, the axial-ratio value within 3 dB is 45 degree and the cross-polarization levels in zenith direction are less than -23 dB at 1900 MHz. This results indicate that the proposed antenna realizes a good circularly polarization performance.